renamed inc -> increment

added decrement as well (pre-decremented)

test/lib/liquid/tags/inc_tag_test.rb

@@ -0,0 +1,25 @@
+require 'test_helper'
+
+
+class IncTagTest < Test::Unit::TestCase
+  include Liquid
+  
+  def test_inc
+    assert_template_result('0','{%increment port %}', {})
+    assert_template_result('0 1','{%increment port %} {%increment port%}', {})
+    assert_template_result('0 0 1 2 1',
+                           '{%increment port %} {%increment starboard%} ' +
+                           '{%increment port %} {%increment port%} ' +
+                           '{%increment starboard %}', {})
+  end
+
+  def test_dec
+    assert_template_result('9','{%decrement port %}', { 'port' => 10})
+    assert_template_result('-1 -2','{%decrement port %} {%decrement port%}', {})
+    assert_template_result('1 5 2 2 5',
+                           '{%increment port %} {%increment starboard%} ' +
+                           '{%increment port %} {%decrement port%} ' +
+                           '{%decrement starboard %}', { 'port' => 1, 'starboard' => 5 })
+  end
+
+end